Cosmic rays could power subsurface life in the universe

This site may earn affiliate commissions from the links on this page. Terms of use.

Dimitra Atri, from the Blue Marble Space Institute of Science in Seattle, just dropped a curious paper into the official Arxivbin of open knowledge. In it, he discusses the possibility that life in subsurface environments — places where photosynthesis is a non-starter — could eke out a living by feeding upon cosmic rays. Rather than consuming them directly, as they are much too potent for that, life would extract their secondary energy via a mechanism known as radiolysis.

We need look no further than hot springs or seafloor hydrothermal vent systems to find subsurface life capable of sustaining minimal metabolisms from purely geothermal or geochemical sources. Perhaps more surprisingly, bacteria found deep in the mines of South Africa have been found to subsist via radiolysis. Specifically, they consume hydrogen formed through the emissions of radioactive U, Th, and K in the surrounding rock.

There is another source of radiation available in subsurface environments, and that’s the one Atri has zeroed in on. Galactic cosmic rays produce a small but steady stream of secondary particles known as muons. Muon-induced radiolysis can generate H2, which can be harnessed by methanogens for abiotic (inorganic) hydrocarbon synthesis. Methanogens are not bacteria per se, but are generally classified as members of kingdom ‘Archaea.’ Methanogens, which you can find more about here, produce methane as a metabolic product in anoxic conditions.

Atri suggests muon-induced radiolysis isn’t the only mechanism available to cosmic-ray-powered life. Organic synthesis from other secondaries created in cosmic ray particle showers would be theoretically possible. Direct capture of radiation through the use of pigments like melanin is also conceivable. Although melanin is a fairly complex molecule, it is ubiquitous in most biological kingdoms. In addition to its more familiar use in absorbing radiation as a shield, it can also transduce radiation and transmit its energy to other metabolic processes.

To make melanins, creatures like us avail themselves of all the higher order synthetic tools Eukaryotes have at their disposal — coding and transcription in the isolated nuclear DNA, translation in the cytosol, and ultimately polymerization into a large polymer. However, the basic building blocks of melanin appear to be most simply manufactured by oxidation of the familiar amino acid tyrosine, followed by linking them into chains. It is not clear how or under what conditions more primitive life could might pull off melanin synthesis, but other radiation handling molecules might be used as well.

Dimitra’s proposal of a cosmic ray origin for a potential radiolysis-powered ecosystem may be a fairly big step further than anything we have seen. However, naturally occurring organisms fueled by radiation continue to be discovered here on Earth and could potentially be found surviving beyond. The deep-mine dwelling Desulforudis bacterium we mentioned above, for example, has no known access to light, oxygen, or organic hydrocarbon sources. Yet it has found a way to extract carbon from dissolved CO2 and nitrogen from rock at extreme temperatures that would cook other organisms.

Desulforudis protects its large genome from harsh acidic conditions, lack of water, and DNA-crippling radiation, by a combination of repair mechanisms, cyst-formation, and generally scrappiness. Proving Atri’s particular conceptions would be possible — let alone likely — may require actually finding organisms that have achieved this somewhere. That could be on Earth, the Moon, or perhaps someplace like Europa. Before anyone is too quick to dismiss the power of cosmic rays, we might mention one testimonial: Bill Nye, The Science Guy, has recently, and unabashedly, attributed the welcome return to life of his ailing solar sail craft to a lone cosmic ray.

Tagged In

This site may earn affiliate commissions from the links on this page. Terms of use.

ExtremeTech Newsletter

Subscribe Today to get the latest ExtremeTech news delivered right to your inbox.

Email

This newsletter may contain advertising, deals, or affiliate links. Subscribing to a newsletter indicates your consent to our
Terms of Use and
Privacy Policy. You may unsubscribe from the newsletter at any time.